This invention relates to a press die system for producing blanks from a sheet of material, and particularly to a guide system for releasing a plurality of blanks arranged in nested relation from a gravity feed die to aid in preventing jamming of the die.
In recent years, the popularity of oval-shaped paper plates and trays has increased. Consumer plate and tray shape preferences have changed and manufacturers have responded by attempting to provide suitable alternatives to the standard round and rectangular shapes. It will be appreciated that other oblong shapes having straight and curved edges are also becoming more popular with consumers.
One problem with the manufacture of an oval plate or tray shape as compared to rounds or rectangulars is that sheet material is generally wasted during conventional blanking operations. It will be appreciated that "trim" waste can be reduced by setting up a press to "nest" the oval blanks together in closely packed relation to one another on the sheet material to be blanked. However, a significant amount of sheet material is wasted by forming oval-shaped plate or tray blanks in a standard, regimented, columnar array using conventional web-feed presses that are unable to "nest" the oval blanks. Known presses are unable to release nested blanks without causing one or more of the blanks to jam the machine during ejection.
One object of the present invention is to provide reliable means for releasing blanks from a die configured to run the blanks close together, e.g., in "nested" relation.
Another object of the present invention is to provide means for guiding adjacent blanks falling under gravity through a die away from each other and away from certain portions of the die to reduce the likelihood that the die will be jammed due to entanglement of the blanks with each other and with the die itself.
According to the present invention, a press die system is provided for producing blanks from a sheet or web of material. The press die system includes an inclined die shoe having a blank delivery region, partition means for dividing the blank delivery region into a plurality of individual exit regions, and blanking means for piercing the sheet or web of material in a predetermined pattern. The press die system further includes guide means for guiding each of the blanks generated by the blanking means along a separate blank transfer path toward a companion exit region. The guide means is configured to define a blank transfer plane extending across the blank delivery region. Ramp means is provided for tilting blanks guided along at least one of the blank transfer paths relative to the blank transfer plane to reduce the number of jamming incidents that would otherwise occur along said at least one of the blank transfer paths.
In use, the blanking means generates a plurality of blanks that are deposited into the inclined die shoe and arranged to fall under gravity onto the guide means for movement toward the individual exit regions. The ramp means acts to move blanks guided along a particular blank transfer path laterally in relation to an adjacent blank transfer path by tilting the blanks. Lateral blank movement as a result of tilting aids in preventing entanglement of blanks falling through the press die system with other blanks and with portions of the press die system itself.
In preferred embodiments of the present invention, the press die system further includes a cutting die plate having a surface for supporting the sheet or web of material and a plurality of blank discharge apertures shaped to discharge oval plate or tray blanks and arranged in a "nested" pattern. The partition means forms a plurality of blank transfer lanes in the die shoe that are situated underneath the cutting die plate to provide outer boundaries for the blank transfer paths. Blanks are conducted out of the die under gravity along these blank transfer lanes. Each blank transfer lane extends from an entrance region positioned in alignment with only one of the overlying blank discharge apertures to its individual exit region.
Inclination of the die shoe causes blanks deposited into each blank transfer lane by the blanking means to fall under gravity along a transfer path toward the exit region. The partition means includes a partition member situated intermediate each pair of adjacent blank transfer lanes to aid in preventing movement of a blank from one blank transfer lane to an adjacent blank transfer lane during gravity discharge of the blanks from the die.
Pairs of first guide rails are situated in substantially coplanar spaced-apart relation in most of the blank transfer lanes to form the guide means. However, at least one of the blank transfer lanes is a specially configured "anti-jamming lane". Such a lane is generally situated in or near an outermost portion in the die shoe along a longitudinal boundary edge of the blank delivery region. Instead of the companion pair of first guide rails, the anti-jamming lane includes a first guide rail aligned in substantially coplanar relation with the pairs of first guide rails provided in other lanes and a second guide rail configured to provide the ramp means.
The second guide rail desirably includes a downstream portion that is positioned in proximity to the exit region of the designated anti-jamming lane and aligned in substantially coplanar relation to its companion first guide rail. The second guide rail further includes an upstream portion made of a resilient material that extends into the entrance region of the anti-jamming lane and is canted at a compound angle in relation to the companion first guide rail. Thus, the canted second portion is inclined to slope downwardly within the anti-jamming lane in a direction away from the immediately adjacent blank transfer lane toward the exit region of the anti-jamming lane and away from the partition member situated between the anti-jamming lane and the immediately adjacent blank transfer lanes.
The features of the present invention advantageously make feasible gravity discharge of blanks from a die shoe assembly set up to cut "nested" blanks from a web of sheet material by providing a reliable means of releasing the blanks from the die shoe assembly without entangling the blanks and thereby jamming the die. The novel release feature is generally positioned in outermost blank transfer lanes experiencing frequent jamming problems. This release feature causes the blanks in such designated "anti-jamming" lanes to move laterally in the die away from potential entanglement locations before falling out of the die through the exit region.
Lateral movement of the type described above is particularly desirable in nested blanking operations of the type forming forward and rearward lines or series of blanks extending across the width of the die shoe in which blanks in the forward series alternate in staggered, nested relation with blanks in the rearward series. This nested blanking pattern is desirably used in forming in substantially oval-shaped blanks to reduce trim waste of the blanking material in a most advantageous manner. Identification of frequently jammed blank transfer lanes best suited for inclusion of the release feature and the most advantageous location of the release feature will be explained in greater detail in the detailed description of the drawings set forth below.
One feature of the present invention is the provision of ramp means in a designated anti-jamming lane for guiding blanks moving under gravity through a selected blank transfer lane in a lateral direction away from an adjacent blank transfer lane. This feature advantageously releases blanks from the die in a reliable manner by moving "neighboring" blanks traveling along adjacent paths apart from one another. This separating movement reduces the risk of jamming the die due to entanglement of the neighboring blanks with each other about the partition members situated between the adjacent paths.
Another feature of the present invention is the provision of a canted guide rail in the designated anti-jamming lane. This canted guide rail extends into the entrance region of the anti-jamming lane to lie within a "blank discharge zone" extending between the support surface of the cutting die plate and the die shoe. The canted guide rail is made of a resilient material to intercept blanks falling under gravity through the blank discharge zone from the overlying blank discharge aperture, and yieldably urge those blanks toward the individual exit region of the designated anti-jamming lane in the above-described lateral anti-jamming direction.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.